It is in the prior art to use aliphatic diesters of dicarboxylic acids as efficient lubricants, hydraulic fluids, cutting oils, etc. Indeed, on the basis of present theoretical knowledge and practical experience, it is possible by precise selection of the ester components to achieve products having very specific properties. Despite their proven efficiency, however, such made-to-order individual esters have a very narrow scope of application and are seldom universally usable, and for this reason it is generally necessary to prepare a special ester oil for each application. For example, on the basis of its physical and chemical properties, the monomeric ester oil which is described in detail in Table 1, Column 1, can be used directly for the lubrication of transmissions and refrigeration machines, but for use as an all weather motor oil must be used in mixtures with mineral oils.